behrens



UNITE@ STATES? PATENT FFICE.

H. J. BEHRENS, OF-NEW YORK, N. Y.

WRENCH.

Specification of Letters Patent No. 13,597, dated September 25, 1855.

To @ZZ wL-om t may concern Be it known that I, H. J. BEHRnNs, of t-he city, county, and State of New York, have invented a new and useful Improvement in IVrenches for Turning Screw-Nuts; and I do hereby declare the following to be a full, clear, and exact description thereof, in which- Figure l, is a side view of the device.

My improvement is for the purpose of cheapening the article below the price of the screw or rack wrenches now in common use, 4while it is made to hold as powerfully as they do and is easily worked with one hand, a feat-ure of great importance in practice.

I am aware that rack wrenches have been made and used a long time. I am also aware that wrenches have been made with smooth bars like mine, illustrations ofv which are shown in Prechtles Technological Encyclopedia., where a wedge is shown attached to the movable jaw to bind it to the bar driven forward by a lever grasped in the hand. A wedge has also been similarly used driven with a hammer to fasten the movable jaw. The objections to .these several devices arethat they are found not to readily fasten the jaw, to unfasten only with considerable exertion, and to be very liable to slip when much strain is put upon the wrench for the obvious reason that the whole force to hold the j aw is derived from the friction of the parts upon each other and the key or wedge having the same amount o-f friction upon the jaw that it has upon the bar is easily moved along with it without any additional binding when greater strains are brought upon the tool so that for every addition of strain upon the wrench a corresponding driving of the wedge is required which if it does not greatly exceed the resistance will allow the jaw to slide. These disadvantages I obviate by employing an eccentric the periphery of which is serrated and hardened so as to produce the maximum of friction upon the bar while it is hung'on a pin in the jaw so as to turn with the minimum of friction there. Thus when the jaw is pressed back by the strain there is but a small amount of friction upon the eccentric to carry it back while its serrated periphery tenac'iously holds upon the smooth bar7 increasing its holding power with each increase of strain and when the strain is removed allowing an easy and expeditious release so that the jaw can be moved back and forth by one hand.

The construction is as follows: a is a square smooth bar having a stationary jaw at one end and a sliding jaw Z) of common form sliding on the bar. This jaw has on its rear side above a bearing for the pivot (l of the eccentric c. This eccentric by turning bears with its periphery upon the bar and the part of the periphery which comes in contact with the bar is serrated so as to insure its hold thereon. There is a thumb piece projecting up from the bar at e, between which and the jaw there is a spring z' which forces down the eccentric upon the bar when it is not pressed back by the fingers. The pin that holds the eccentric to the jaw is made to project as seen in F ig. 2, so as to give a hold to draw the jaw back by. This is necessary when the two jaws are closed together and also to enable me to move the jaw with one hand at all times with facility. This pin is loose and can be slid through so as to come flush with the side in places where it would be an obstacle.

Having thus fully described my improved wrench and pointed out its variation from what before has been done what I claim is- The employment of an eccentric toothed on its periphery and held down by a spring as described in combination with the smooth bar wrench in the manner and for the purpose herein set forth.

HENRY J. BEHRENS.

Vitnesses:

lJACOB HATZEL, Jr., J. C. GREENOUGH. 

